I don't have a drive by video of my Kooks headers and NPP, but I can tell you it sounds amazing...
If it means anything, here is my dyno video (sound isn't perfect I filmed from a distance with my phone...)

There will not be much deviation in sound with headers from brand to brand. Just about any 4-1 style header will sound similar. It's when you get into the 4-2-1 headers that the sound changes a little bit.